## space-time metric

*c squared d tau squared equals the sum from mu and* *nu equal one to four of g sub mu nu of x d x super mu* *d x super nu, equals g sub mu nu of x d x super mu d x* *super nu.*

*c squared d tau squared equals the sum from mu and* *nu equal one to four of g sub mu nu of x d x super mu* *d x super nu, equals g sub mu nu of x d x super mu d x* *super nu.*